This invention belongs to the field of textile finishing means of liquors which contain textile fiber treatment agents. It refers especially to the continuous application of liquors, particularly treatment or, finishing liquors including dyeing liquors, on advancing textile fiber webs where these liquors are absorbed. The invention is furthermore related to apparatuses for carrying out the process.
A plurality of processes and working techniques are already known in the field of textile processing which allow the application of liquors or bathes on textile material webs. In a manner known per se, the term "web" means a textile material which is absorptive for liquids and whose length, compared to its width, is very great, for example 500 to 10,000 times the width, the latter typically not exceeding about 3 meters. The thickness of the material is normally comprised between one and about ten times the diameter of the fibers or filaments forming said textile material. This term therefore comprises woven and knitted fabrics, other non-woven materials such as vleeces, and furthermore also rows or sheets of parallel warp yarns which are to be sized or dyed before weaving. In the latter case, the thickness of the web may be greater than ten times the yarn diameter.
Examples of such liquor application methods are padding, slop padding, the different impregnating techniques, spraying, liquor application which sponges, application of foam and printing; in most cases it is necessary or advantageous to first apply an excess of liquor and then to remove said excess.
An important liquor application method which guarantees a homogeneous impregnation of the web, is the pad mangle technique. In this method, the textile web is offered as much as liquor it will absorb, and the excess of liquor is then removed between squeezing rollers. It is impossible to remove any liquor below the so-called water retention value of the textile material. When technically reasonable squeezing pressures are used, the amount of liquor remaining in the textile material is greater than that limiting value.
The pad mangle technique may be put into practice in different ways, see. e.g., Peter, Grundlagen der Textilveredlung, Dr. Spohr editor, 10th ed., 1970, p. 56 and following, or other manuals of textile processing. These techniques and methods are known to the man skilled in the art. Generally, one proceeds in the following manner: A dry textile web or an already liquor containing web is fed through a trough containing the liquor to be applied. The soaked textile material is then passed in a squeezing roller device where the excess of soaked liquor is removed. It is also possible to pass the textile web to be padded vertically from above through the roller nip of a horizontal squeezing device and to fill the liquor to be applied into the space above the two squeezing rollers. This will result in the presence of a wedged shaped liquor pool or liquor gore at both sides of the textile web just before it enters the roller gap, said liquor supply being of course maintained to replace the amount currently taken up by the textile web.
The particulars and difficulties of the pad mangle technique are known to the man skilled in the art. In particular, the control of the liquor amount to be applied is only possible within relatively narrow limits and can only be achieved via the liquor composition or concentration and/or the squeezing pressure of the squeezing rollers. Nevertheless, pad mangling has advantages in many impregnating processes and is carried out until now, the devices being continuously improved.
A further, important method for the application of liquors, particularly of finishing liquors, on textile material webs is the so-called MA process (MA stands for minimum application) introduced in the '70s. This process allows a homogeneous, controlled and sub-excess impregnation of textile webs with increased working speeds. It is disclosed, as well as a preferred apparatus for its performing, in U.S. Pat. Nos. 3,862,553 and 3,822,834, respectively, and does not need any squeezing device. The process in now introduced in a world-wide scale, is perfectly well known in the field of textile finishing, and need not further be described here.
Although the MA process has been known as a minimum application process, it may also be used for the application of higher amounts of liquors in a controlled, metered and homogeneous manner. This alternative method will be designed in the following, comprising also the minimum application, as "metering roller application".
It has been found, some time ago, that it would be highly desirable for a number of cases to develop a process and an apparatus allowing the operation of pad-mangling as well as the metering roller application, in one and the same machine assembly.
A solution of this problem which appears to be within the ordinary skill of the textile engineer, has already been proposed by the applicants. This solution comprises the successive arrangement of a pad mangle and a metering roller device in one machine frame. One of the two devices may thus be used at will. However, this solution has some serious drawbacks. Firstly, when the change from one to the other application device is desired, the textile web must be cut, drawn completely out of the machine, and be introduced freshly from the infeed end of the machine into and through the other one of the said two applicator devices. This procedure is necessary since the impregnated textile web cannot be allowed to touch any other rollers, not used for the particular, selected application method, before entering the drying section. Secondly, it is expensive and therefore uneconomical to provide two fully separated applicator devices together with the necessary, complex auxiliary and secondary devices, one of these apparatus assemblies being always out of operation; therefore, this solution could not be introduced commercially.